Research on genetics and physiology of Salmonella typhimurium will deal especially with three topics: (1) Lipopolysaccharide and protein components of outer membrane, in particular: mapping of rfa genes, determining LPS core structure: nature of defect in part-rough and "FOR" (smooth but non-virulent) LPS mutants: bacteriocin receptors: and effect of relevant mutations on survival within phagocytic host cells (mouse). (2) Genetics and physiology of motility and chemotaxis: especially correlation of che, mot and fla genes of Salmonella with E. coli; mapping of uvrC in relation to fla, etc., in Salmonella; studies of dominant che alleles. (3) Genetics and physiology of plasmids in S. typhimurium, especially: role of host UV-resistance, recombination and related genes, and of molecular oxygen, in UV-protection, enhancement of UV-mutagenesis and mutator effect of plasmid R46, and of mutator effect only of plasmid pKM115; mechanism of retardation of growth of E. coli on defined medium by presence of R46; characterization of group E and related colicins and plasmids. BIBLIOGRAPHIC REFERENCES: Integration, at hag or elsewhere, of H2 (phase-2 flagellin) genes transduced from Salmonella to Escherichia coli. Enomoto, M., and Stocker, B.A.D. (1975) Genetics, 81:595-614. Ultraviolet-protection, enhancement of UV-mutagenesis and mutator effect of plasmid R46 in Salmonella typhimurium. Mortelmans, K.E., and Stocker, B.A.D. (1976) J. Bacteriol, in press.